How can I promote simple plugin for wordpress?

Now I having on my simple plugin Facebook Like Button for every post on your wordpress site (blog). Now I have ~300 downloads and ~50 active installs.

How can I promote my this simple plugin for wordpress on Can I develop and create paid version of my plugin and selling him on codecanyon?

There’re lots of free “like” plugins out there. I don’t think anyone would pay to get one while they could download it for free
( Depends on the features but it’s “Like” plugin. You cannot offer lots of things )